Slide Show: Jellyfish Jamboree--Are They Set to Seize the Seas?

Bloomin' jellyfish! Overfishing, climate change and ocean dead zones may be downers for humans and other critters, but they turn out to be a boon for jellyfish schools, reports the recent "Jellyfish Joyride" paper in Trends in Ecology and Evolution.

A surge in jellyfish populations may eventually lead to what study authors call "a less desirable gelatinous state," which could have "lasting ecological, economic and social consequences."

Swimming safely in aquariums, jellyfish might look like rare, delicate creatures, but many species are quite hardy—not to mention, harmful. Aside from bothering beachgoers, they've been known to wreck fishing nets and actually kill swimmers. The heftier jellies, such as the Nomura (Nemopilema nomurai) can reach diameters of 6.5 feet (2 meters) and weigh as much as 440 pounds (200 kilograms).

About 470,000 tons (425,000 metric tons) of jellyfish are already harvested for fine dining in Southeast Asia every year. Are we looking at a future of jellyfish burgers and popcorn polyps?

Not all scientists are convinced that a gelatinous takeover is on the horizon. "There is some debate about this issue," says Jack Costello, a professor of biology at Providence College, who wasn't involved in the study. Some species of jellyfish aren't tolerant to new and changing ocean conditions and actually seem to be in decline, he notes.

But there's one thing jellyologists agree on: we still have a lot to learn about these mysterious creatures.